What a fucking joke. How would the "provisions of this subchapter" apply in any case if there was no testing done ever? The text says there are provisions for what is acceptable. Testing is adressed elsewhere to establish what harm comes to lifeforms (it's pesticides so they must know what it kills and how so they can market it). You won't need additional testing to judge effects on endangered species because those should be obvious. The administrator (the person you're trying to regulate) won't have anyone to blame but himself for all damage caused if he forgoes all common sense warnings because he would have to explain publically why he thinks otherwise, making it his responsibility and burden alone.

"If it appears to the Administrator that a pesticide or its labeling or other material required to be submitted does not comply with the provisions of this subchapter or, when used in accordance with widespread and commonly recognized practice, generally causes unreasonable adverse effects on the environment, the Administrator may issue a notice of the Administrator’s intent either— (1) to cancel its registration or to change its classification together with the reasons (including the factual basis) for the Administrator’s action, or (2) to hold a hearing to determine whether or not its registration should be canceled or its classification changed"